The present invention relates to an X-ray CT (computed tomography) apparatus and a method of controlling the same. More specifically, the invention relates to an X-ray CT apparatus for acquiring an image of a subject by a helical scan synchronized with a heart beat and to a method of controlling the same.
In the case of imaging heart by an X-ray CT apparatus, a scan is performed while collecting a heart beat signal, and an image is reconstructed by using projection data of an amount of a half scan in a desired heart beat phase. The scan is performed as a helical scan, and a multi-row X-ray detector is used for acquiring projection data. The X-ray CT apparatus using the multi-row X-ray detector is also called an MDCT (Multi Detector Row CT).
Imaging of the heart by an MDCT, the helical pitch is set in accordance with the heart beat so that all of heart beat phases in slice images in a plurality of continuous slice positions become the same and no dropout of projection data occurs between neighboring slice positions (refer to, for example, Japanese Patent Laid-Open No. 2005-137390).
To improve time resolution of image acquisition, projection data of an amount of a half scan is collected in a plurality of heart beats. Image reconstruction based on the projection data collected in such a manner is also called multi-sector reconstruction.